glsl: calculate number of operands in an expression once

Extra validation is added to ir_validate to make sure this is
always updated to the correct numer of operands, as passes like
lower_instructions modify the instructions directly rather then
generating a new one.

The reduction in time is so small that it is not really
measurable. However callgrind was reporting this function as
being called just under 34 million times while compiling the
Deus Ex shaders (just pre-linking was profiled) with 0.20%
spent in this function.

v2:
 - make num_operands a unit8_t
 - fix unsigned/signed mismatches

Reviewed-by: Thomas Helland <[email protected]>

1 files changed, 20 insertions, 2 deletions

diff --git a/src/compiler/glsl/ir.cpp b/src/compiler/glsl/ir.cpp
index 78889bd6d3f..51b875058b1 100644
--- a/src/compiler/glsl/ir.cpp
+++ b/src/compiler/glsl/ir.cpp
@@ -203,11 +203,16 @@ ir_expression::ir_expression(int op, const struct glsl_type *type,
    this->operands[1] = op1;
    this->operands[2] = op2;
    this->operands[3] = op3;
+   init_num_operands();
+
 #ifndef NDEBUG
-   int num_operands = get_num_operands(this->operation);
-   for (int i = num_operands; i < 4; i++) {
+   for (unsigned i = num_operands; i < 4; i++) {
       assert(this->operands[i] == NULL);
    }
+
+   for (unsigned i = 0; i < num_operands; i++) {
+      assert(this->operands[i] != NULL);
+   }
 #endif
 }
 
@@ -221,6 +226,9 @@ ir_expression::ir_expression(int op, ir_rvalue *op0)
    this->operands[3] = NULL;
 
    assert(op <= ir_last_unop);
+   init_num_operands();
+   assert(num_operands == 1);
+   assert(this->operands[0]);
 
    switch (this->operation) {
    case ir_unop_bit_not:
@@ -425,6 +433,11 @@ ir_expression::ir_expression(int op, ir_rvalue *op0, ir_rvalue *op1)
    this->operands[3] = NULL;
 
    assert(op > ir_last_unop);
+   init_num_operands();
+   assert(num_operands == 2);
+   for (unsigned i = 0; i < num_operands; i++) {
+      assert(this->operands[i] != NULL);
+   }
 
    switch (this->operation) {
    case ir_binop_all_equal:
@@ -519,6 +532,11 @@ ir_expression::ir_expression(int op, ir_rvalue *op0, ir_rvalue *op1,
    this->operands[3] = NULL;
 
    assert(op > ir_last_binop && op <= ir_last_triop);
+   init_num_operands();
+   assert(num_operands == 3);
+   for (unsigned i = 0; i < num_operands; i++) {
+      assert(this->operands[i] != NULL);
+   }
 
    switch (this->operation) {
    case ir_triop_fma: